Study on the enhancement of phase change thermal storage performance by biomimetic horseshoe (BH) shaped pipe structure coupled with fins and nanoparticles

Effective energy storage technology is needed due to rising worldwide industrialization. Although phase change materials (PCM) have great energy storage density, their low thermal conductivity limits their use. The single enhancement method struggles to tackle multi-scale thermal resistance. For this, a multi-scale cooperative system of “bionic horseshoe-shaped tube-fin-nanofluid” is developed, and multi-physics coupling technology simulates the phase transition. The results show that the 7 horseshoe-shaped structure shortens the melting time of PCM by 36.11 % and increases the heat transfer efficiency by 43.29 % by expanding the heat exchange area and inducing the flow field disturbance, which confirms the key role of geometric optimization in thermal enhancement. In addition, the 10 mm V-shaped fin reduced the melting time by 19.84 %, demonstrating a quantitative relationship between fin diameter and convection efficiency. The system with 0.01 volume fraction of SiO₂ nanofluids reduces melting time to 27 min, a 21.28 % improvement over pure PCM, demonstrating the benefits of nano-reinforcement and structural optimization. At 363.15 K, it increases thermal efficiency by 66.86 % and enhances heat storage uniformity. This research introduces a multi-scale collaborative design for latent heat storage systems, advancing the efficient use of renewable energy.